This invention is directed to a method of producing fully encircling, curved leg elastics. The method involves placing a pair of elastic ribbons on a pair of disks that rotate off-center to provide a camming function, and subsequently applying the elastic ribbons to a substrate.
Pant-like absorbent garments, such as adult incontinence wear, as well as infant and children""s diapers, swim wear and training pants, typically include a pair of leg openings having an elastic portion around each leg opening. The elastic portions are intended to fit snugly around a wearer""s legs to prevent leakage from the garment.
Various technologies are known for applying leg elastics to such articles. For example, one technology involves bonding a continuous loop to a substrate. However, producing a supply of continuous loops of elastic strands is more costly and cumbersome than providing a supply of a continuous length of elastic ribbons.
Articles which incorporate conventional elasticized margins and conventional barrier flap configurations at their leg openings have, however, exhibited various shortcomings. For example, it has been difficult to avoid pressure-induced marking of the wearer""s skin and difficult to maintain the desired gasketing of the leg openings when the articles are being worn. Even when the leg openings are fitted with an elastomeric material or otherwise elasticized, it has been difficult to maintain contact between the leg opening and the wearer""s body for effective containment of urine and feces. As a result, there has been a continued need for improved containment structures at the leg regions of absorbent articles.
There is a need or desire for a process for making comfortable, gasket-like leg elastics that are aesthetically pleasing and can be applied in a high-speed application.
The present invention is directed to a method of applying curved leg elastics to pant-like absorbent garments using disks that rotate off-center. Apparatus that can be used for carrying out the invention includes at least one pair of rotating disks, a cutting device, and a bonding device. The rotating disks have a curved surface around which an elastic ribbon is stretched. The result is a comfortable, flexible, aesthetically pleasing leg opening. Furthermore, the resulting leg opening is form-fitting and acts like a gasket.
In carrying out the invention, each elastic ribbon of a pair of elastic ribbons is guided onto one of the disks. The elastic ribbon is guided onto the pucks such that a portion of the elastic ribbon overhangs the edge of the first curved surface. Tension in the elastic ribbon causes the overhanging portion to fold over onto an adjacent, second curved surface of the puck. The disk is juxtaposed to a substrate to which the elastic ribbon will be applied. The disk rotates about a point significantly off-center from a center of the disk, thereby providing an oscillating motion towards the substrate. The second portion of the elastic ribbon is bonded to the substrate.
The elastic ribbons are cut into discrete lengths prior to carrying out the method of the invention by using a slip cut applicator. The elastic ribbon is fed onto an anvil of a slip cut unit. The anvil is suitably wide enough to support a fall width of the elastic ribbon to enable easy cutting with a knife portion of the slip cut unit. The cut segment of elastic ribbon is then transferred to the disk and held in place with a vacuum.
The method of the invention can be used in high-speed applications, namely applications running at linear speeds of 600 feet per minute or greater. The substrate may be stretchable or extensible, thereby providing great flexibility and enabling the elastic ribbons to be applied at low tension. Furthermore, stretchability and/or extensibility of the substrate provide for a larger leg fit range.
The resulting product is an absorbent garment having a comfortable, aesthetically pleasing, finished look about the leg openings. This method can also be used to apply curved standing leg cuffs and/or curved leak guard flaps.
With the foregoing in mind, it is a feature and advantage of the invention to provide a method of applying curved leg elastics to an absorbent garment.
It is another feature and advantage of the invention to provide a method of applying leg elastics to an absorbent garment resulting in gasket-like leg openings.
It is yet another feature and advantage of the invention to provide a method of applying leg elastics to an absorbent garment resulting in form-fitting leg openings.
It is a further feature and advantage of the invention to provide a method of applying leg elastics to an absorbent garment resulting in comfortable and aesthetically pleasing leg openings.